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Date:   Fri, 25 Nov 2022 14:44:37 +0100
From:   Andrea Righi <andrea.righi@canonical.com>
To:     Alexandre Ghiti <alex@ghiti.fr>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: increase boot command line size to 1K
Message-ID: <Y4DGxWLIVx9p9TS+@righiandr-XPS-13-7390>
References: <20221125133713.314796-1-andrea.righi@canonical.com>
 <6fee29f8-8150-e6ec-e2ec-210610a7e27d@ghiti.fr>
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On Fri, Nov 25, 2022 at 02:41:11PM +0100, Alexandre Ghiti wrote:
> Hi Andrea,
> 
> On 11/25/22 14:37, Andrea Righi wrote:
> > Kernel parameters string is limited to 512 characters on riscv (using
> > the default from include/uapi/asm-generic/setup.h).
> > 
> > In some testing environments (e.g., qemu with long kernel parameters
> > string) we may exceed this limit, triggering errors like the following:
> > 
> > [    3.331893] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000
> > [    3.332625] CPU: 2 PID: 1 Comm: sh Not tainted 6.1.0-rc6-kc #1
> > [    3.333233] Hardware name: riscv-virtio,qemu (DT)
> > [    3.333550] Call Trace:
> > [    3.333736] [<ffffffff800062b6>] dump_backtrace+0x1c/0x24
> > [    3.334053] [<ffffffff806e8f54>] show_stack+0x2c/0x38
> > [    3.334260] [<ffffffff806f2d06>] dump_stack_lvl+0x5a/0x7c
> > [    3.334483] [<ffffffff806f2d3c>] dump_stack+0x14/0x1c
> > [    3.334687] [<ffffffff806e92fa>] panic+0x116/0x2d0
> > [    3.334878] [<ffffffff8001b0aa>] do_exit+0x80a/0x810
> > [    3.335079] [<ffffffff8001b1d0>] do_group_exit+0x24/0x70
> > [    3.335287] [<ffffffff8001b234>] __wake_up_parent+0x0/0x20
> > [    3.335502] [<ffffffff80003cee>] ret_from_syscall+0x0/0x2
> > [    3.335857] SMP: stopping secondary CPUs
> > [    3.337561] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000000 ]---
> > 
> > It seems reasonable enough to increase the default command line size to
> > 1024, like arm, to prevent issues like the one reported above.
> > 
> > Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
> > ---
> >   arch/riscv/include/asm/setup.h      | 7 +++++++
> >   arch/riscv/include/uapi/asm/setup.h | 7 +++++++
> >   2 files changed, 14 insertions(+)
> >   create mode 100644 arch/riscv/include/asm/setup.h
> >   create mode 100644 arch/riscv/include/uapi/asm/setup.h
> > 
> > diff --git a/arch/riscv/include/asm/setup.h b/arch/riscv/include/asm/setup.h
> > new file mode 100644
> > index 000000000000..f4fe549aab40
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/setup.h
> > @@ -0,0 +1,7 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +#ifndef __ASMRISCV_SETUP_H
> > +#define __ASMRISCV_SETUP_H
> > +
> > +#include <uapi/asm/setup.h>
> > +
> > +#endif /* __ASMRISCV_SETUP_H */
> > diff --git a/arch/riscv/include/uapi/asm/setup.h b/arch/riscv/include/uapi/asm/setup.h
> > new file mode 100644
> > index 000000000000..5738f93ae437
> > --- /dev/null
> > +++ b/arch/riscv/include/uapi/asm/setup.h
> > @@ -0,0 +1,7 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _UAPI__ASMRISCV_SETUP_H
> > +#define _UAPI__ASMRISCV_SETUP_H
> > +
> > +#define COMMAND_LINE_SIZE 1024
> > +
> > +#endif /* _UAPI__ASMRISCV_SETUP_H */
> 
> 
> Just for reference to previous discussions regarding this: https://lore.kernel.org/lkml/CACT4Y+YYAfTafFk7DE0B=qQFgkPXS7492AhBdY_CP1WdB8CGfA@mail.gmail.com/T/
> 
> Thanks,
> 
> Alex

Ah! It has been address/discussed already, great! Thanks for pointing
that out and sorry for the unnecessary patch. :)

-Andrea